Yemeni forces aligned with the Houthi rebels fired a ballistic missile at an air base deep inside Saudi Arabia, Houthi media said on Monday, while the US said one of its naval vessels had been fired on from Houthi-controlled territory.
The developments came two days after airstrikes, apparently by a Saudi-led and US-backed coalition, killed some 140 people at a funeral in Yemen's rebel-held capital Sana'a that was being attended by high-ranking officials.
Saudi Arabia said it had intercepted a missile fired at the city of Taif, 500 kilometres from the Yemeni border, as well as another fired at an area in eastern Yemen controlled by forces aligned with Saudi-backed President Abd Rabu Mansour Hadi.
The Houthis' al-Masirah television said that the Yemeni army and militias fired a ballistic missile at the King Fahd air base in Taif, claiming that it had hit its target.
The Houthi-controlled Saba news agency meanwhile quoted an unnamed military source denying that the army or rebels had fired on any ships off the Yemeni coast, after the US said one of its naval vessels had detected two inbound missiles on Sunday night.
Both missiles had fallen short of their target and hit the water, according to the Pentagon statement, which said they appeared to have been fired from Houthi-held territory.
Washington has said it is reviewing what it described as "our already significantly reduced support to the Saudi-led coalition" after the attack on the Sana'a funeral hall.
The US has flown more than 5,000 refuelling missions in support of the coalition air campaign, as well as supplying military equipment.
Colonel John Thomas of US Central Command said that the US has provided aerial refueling to the Saudis when necessary. It did not do so the day of the Sana'a strike, but did on the following day, he added.
Thomas said the US has never provided "targeting assistance" to the coalition and that its technical assistance unit in Saudi Arabia, the Joint Command Planning Advisors group, has recently been reduced from 45 to 5 personnel.
US State Department spokesman John Kirby last month said Washington had repeatedly raised concerns with Riyadh about "the lack of precision in some strikes," but argued that Saudi Arabia was acting in self-defence.
Saudi Arabia has denied responsibility for Saturday's attack, but it controls the airspace over Sana'a and no other force is known to have carried out airstrikes there.
In Sana'a, meanwhile, city governor Abdul-Qadir Hilal, one of the highest-ranking victims of the funeral hall strike, was buried, Saba reported.
Saudi Arabia launched its air campaign against the Houthis in March 2015 after they marched on Hadi's last strongholds in southern Yemen.
The intensified conflict since then has cost thousands of lives and left many Yemenis short of food, safe drinking water and medical care.
The UN has called for an end to the Saudi-led airstrikes since September last year, saying they are responsible for the majority of the conflict's civilian casualties.
International medical charity Doctors without Borders (MSF) pulled out of northern Yemen in August following a Saudi-led airstrike at one of its facilities that killed 19 people.
The Houthis and allied forces, including military units loyal to former president Ali Abdullah Saleh, have also been accused of causing numerous civilian casualties, notably in the reported shelling of residential areas in the central city of Taiz.
UN-sponsored peace talks between representatives from Hadi's government, the rebels, and Saleh's political party ended in Kuwait in August without a breakthrough.
Riyadh fears the Houthis will give Shiite Iran - a key adversary of Sunni Saudi Arabia - a strategic foothold on the Arabian Peninsula.